Fluid pumping and separating apparatus



March 29, 1966 B. H. MOSBACHER 3,242,867

FLUID PUMPING AND SEPARATING APPARATUS Filed March 11} 1964 UnitedStates Patent 3,242,867 FLUID PUMPING AND SEPARATING APPARATUS Bruce H.Mosbaclier, Rockford, Ill., assignor to Roper Industries, Inc.,Rockford, 11]., a corporation of Illinois Filed Mar. 11, 1964, Ser. No.351,053 12 Claims. (Cl. 103-6) This invention relates to improvements influid pumping and separating apparatus.

An important object of this invention is to provide a positivedisplacement type pumping apparatus having expansible and contrac-tiblepumping compartments arranged in an annular bank for centrifugallyseparating and discharging the separated fluid-s in separate streams,and which apparatus is arranged to provide improved radial separation ofthe fluid in the pumping compartments.

A more particular object of this invention is to provide a positivedisplacement type pumping apparatus having a casing and expansible andcontractible pumping compartments arranged in an annular bank forrotation relative to the casing to centrifugally separate the fluids,and which apparatus is arranged to reduce the frictional drag betweenthe fluid in the pumping compartments and the walls of the casing tothereby minimize turbulence and enhance centrifugal separation of thefluids.

An important feature of the present invention resides in the provisionof a pumping apparatus including a rotor defining segregated expansibleand contractible pumping compartments disposed in an annular bank aroundthe rotor, and in which the rotor has plates attached to opposite sidesand overlying the sides of the pumping compartments to enclose thepumping compartments, and wherein the outlet openings are formed in atleast one of the plates adjacent one peripheral wall of the compartmentsand spaced radially from the other peripheral wall of the compartmentsto effect selective discharge of the centrifugally separated materialsfrom the compartments.

These, together with other objects and advantages of this invention,will become apparent as the following detailed description proceeds whentaken in connection with the accompanying drawings wherein:

FIG. 1 is 'a sectional view through the pump and separating apparatustaken on the plane 11 of FIG. 2 and illustrating the-apparatus connectedin a pumping system;

FIG. 2 is a sectional view taken of the plane 2-2 of FIG. 1; and

FIG. 3 is a sectional view through a modified form ofpumping apparatus.

In many applications, such as in lubrication systems, hydraulic controlsystems and fuel delivery systems, it is desirable to deliver the fluidsubstantially free of air and gas. The fluid pumping and separatingapparatus of the present invention not only operates as a positive displacement pump to positively draw the fluid into the pump from a supplyreservoir or the like, but to also provide positive discharge of thefluid under pressure. The ap paratus in general includes a casing,herein shown as a multiple section casing having a body 10, a port plate11, an annular ring 12 defining a pump chamber, and an end plate 13, theseveral parts being held together in assembled relation as by bolts 14.In the embodiments illustrated herein, the pumping apparatus is of thein ternal gear type and includes an annular internally toothed outerrotor 16 which is rotatably supported in the pump chamber for rotationabout the axis of the outer rotor. The rotor 16 is convenientlysupported at its outer periphery on the ring member 12. An externallytoothed inner rotor 17 is disposed within the outer rotor and is3,242,867 Patented Mar. 29, I966 'ice drivingly connected to a shaft 18for rotation about an axis eccentric to the outer rotor. The shaft 18 isconveniently rotatably supported in the body 10 and end plate 13 and isconnected to the inner rotor 17 as by a key 19. The inner rotor has atleast one less number of teeth than the outer rotor and the teeth -17'on the inner rotor are shaped to form a running seal with the teeth 16'on the outer rotor, as the inner and outer rotors rotate about theirrelatively eccentric axes designated A and B in FIG. 1.

The shaft 18 is driven by any suitable means, such as isdiagrammatically indicated at 21 in FIG. 2, to rotate the inner andouter rotors about their respective axes and to centrifugally separatethe fluid in the compartments into radially inner and outer layersaccording to the relative densities of the materials. In the internalgear pump of the type described, the inner and outer peripheral walls ofthe compartments rotate together so that there is little frictional dragat the inner or outer periphery of the compartments. However, the endsof the pumping compartments in an internal gear pump are generallyclosed by the stationary walls of the pump casing. It has been foundthat the resistance or drag imposed on the fluid adjacent the ends ofthe pumping compartments produces turbulence and inhibits completeseparation of the fluid in the compartments into inner and outer layers,particularly when the rotors have a relatively small axial dimension. Inaccordance with the present invention, plates designated 25 and 26 areprovided at opposite ends of one of the rotors. The plates are connectedto one of the rotors for rotation therewith and extend outwardly toenclose the sides of the pumping compartments so that the side walls ofthe pumping compartments rotate therewith and thereby minimize drag andfrictional resistance to rotation of the fluid with the pumpingcompartments. The plates 25 and 26 are preferably secured to the innerrotor and, as shown, are attached thereto by rivets 27. The platesextend outwardly into overlapping relation with the outer rotor 16, asbest shown in FIG. 2, to enclose and seal the ends of the pumpcompartments. At least one of the plates such as 26 is disposed in closerunning fit with the port plate 11 and the other plate 25 on the rotorsis preferably disposed in close running fit with the other end member 13on the pump casing.

At least one of the plates 26 is formed with a plurality of openingstherein and which openings cooperate with ports in the port plate 11 tosupply and exhaust fluid from the pumping compartments. The openings,designated 31, are arranged adjacent one of the peripheral walls of thecompartments to provide selective discharge of the centrifugallyseparated fluids from the compartments. It has been found. preferable todischarge the gaseous fluid first and, accordingly, the openings 31 arelocated closely adjacent the inner periphery of the compartments and arespaced radially inwardly from the outer periphery of the compartments.In the embodiment of FIGS. 1 and 2, the openings 31 are in the form ofholes located at the roots of the .teeth on the inner rotor.

As previously described, the teeth 17 and 16 on the inner and outerrotors form segregated pumping compartments therebetween, which pumpingcompartments progressively expand in one sector of the chamber, that isat the right side of a plane, hereinafter sometimes referred to as theplane of eccentricity, through the axes A and B of the inner and outerrotors, and the compartments progressively contract on the other side ofthat plane. One or more inlet ports are formed in the port plate 11 tocommunicate with the openings 31 as they move past the inlet Zone, andto supply fluid to the compartments during expansion of thecompartments. With fluid to the separating apparatus.

this arrangement, the expanding compartments, positively draw fluidthereinto so that it is unnecessary in many applications to provide aseparate boost pump to supply In the embodiment shown, two inlet portsdesignated 33 and 34 are provide in the port plate 11, it beingunderstood that a single inlet port or a greater number of inlet portsmay be provided, if desired. The inlet ports are located at one side ofthe plane of eccentricity and are angularly spaced apart a distance atleast equal to, and preferably slightly greater than, thecircumferential width of the openings 31 and the plate 26. The inletports 33 and 34 are radially positioned so as to register with theopening 31 as the latter rotate thereby, and the separate ports 33 and34 are conveniently arranged to communicate with different rservoirs,sumps, receptacles or the like designated 38 and 39 in FIG. 1. For thispurpose, port 33 in the plate 11 is connected through a passageway 41 inthe casing body and through a supply line 42 to the reservoir 38. Theother port 34 is connected through a passageway 43 in the pump body andsupply line 44 with the reservoir or receptacle 39.

The fluid from the reservoirs or sumps frequently contain some occludedair and gas, particularly in systems wherein one or the other of thesumps may have some time or other run dry. For example, the reservoirs38 and 39 could correspond to so-called climb and dive sumps in anaircraft engine, which climb and dive sumps receive fluid at relativelydifferent times, depending upon the attitude of the airplane. The pumpand separating apparatus will centrifugally separate the liquid andgaseous fluids, supplied to the apparatus through inlet ports 33 and 34,and discharge the same in separate streams. An air and gas dischargeport designated 46 is provided in the port plate and has one end 46aangularly spaced in the direction of rotation of the pumpingcompartments (indicated by the arrow in FIG. 1) from the end of theinlet port 34. The port 46 is arranged to communicate with the openings31 in the plate 26 during the initial contraction of the compartments.Since the openings 31 are located adjacent the radially inner edge ofthe compartments, that is, adjacent the roots of the teeth on the innergear, the relatively lighter centrifugally separated air and gas isforced outwardly through the openings 31 and through the first outletport 46. The latter is connected through a passage 48 in the pump casingto a conduit 49. This air and gas outlet conduit is convenientlyconnected to one of the reservoirs such as 38, to return the air andgaseous fluid along with any liquid fluid that is separated with the airand gas. An air vent 51 is conveniently provided on the reservoir 38 tovent off the excess gas and air and maintain the reservoir undersubstantially atmospheric pressure.

One or more liquid outlet ports are provided for discharging therelatively heavier liquid from the compartments, during the subsequentcontraction of the same. In the embodiments shown, a single liquidoutlet port designated 53 is provided, it being understood thatadditional liquid outlet ports could be provided and circumferentiallyspaced from each other. The liquid outlet port 53 also has its endsdesignated 53a and 53b angularly spaced from the adjacent outlet port 46and inlet port 33 a distance approximately equal to, and preferablyslightly greater than, the circumferential width of the openings 31 inthe plate 26. The port 53 is radially positioned so as to communicatewith the openings 31 as the compartments rotate past the port 53, tothereby discharge the liquid fluid under pressure through the port 53.The latter is connected through a passage designated 56 to a deliveryline 57 leading to the point of use of the fluid.

A modified form of pumping apparatus is illustrated in FIG. 3, In thisembodiment, the pump casing and the inner and outer rotors areconstructed and formed in the same manner as that described inconnection with FIGS. 1 and 2,' and like numerals are used to designatecorresponding parts. In this embodiment, however, the port platedesignated 26' is'formed with modified openings designated 31'. Theopenings 31 are advantageously made oblong to minimize the radial extentof the openings, While yet providing adequate flow area to preventexcessive restriction to the flow of fluid into and out of the pumpingcompartments. The oblong openings permit the radially outer edge of theopenings to be located closely adjacent the roots of the teeth of theinner gear, to assure discharge of any air from the compartment duringthe initial contraction of the same. In addition, the openings 31' arepreferably located so as to be relatively closer to the side of thecompartment that leads during rotation. In stroboscopic examination ofpositive displacement centrifugal separating apparatus, it was foundthat there was some tendency for the liquid fluid to lag or build uptoward the trailing side of the compartments and force the gaseous fluidtoward the lead side. Olfsetting of the openings 31' in the manner setforth above toward the lead side of the compartments accommodates theabove-described tendency of the fluid to lag in rotation of thecompartments. With the oblong openings, it is, of course, necessary toincrease the spacing between adjacent ports and the port plates so thatthey are spaced apart, a distance approxiamtely equal to, and preferablyslightly greater than, the circumferential width of the opening 31.

In order to minimize the volume of fluid that remains in the pumpingapparatus between the port plate 46 and the pumping compartments, theplate 26 is preferably made relatively thin and, as shown, is very thinas compared to the axial length of the rotors. While openings 31 areherein shown formed in one of the plates 26, it is apparent thatcorresponding openings could be provided in the other plate 25 and apump casing provided with suitable ports and passages to communicatewith the additional openings, to thereby introduce and withdraw fluidfrom both ends of the compartments instead of from a single end as inthe disclosed apparatus.

From the foregoing it is thought that the construction and operation ofthe pump and separating apparatus will be readily understood. The plates25 and 26 rotate with the rotors and enclose the ends of the pumpingcompartment so as to minimize frictional drag and resistance to therotation of the fluid with the. pumping compartments. Since the openings31 and 31' in the rotor plates are located closely adjacent one with theperipheral walls of the pumping compartments, one with the centrifugallyseparated fluids in the compartments will be preferentially dischargedthrough the first port such as 46 while the remaining fluid will bedischarged through the other outlet port 53. In the preferredembodiment, the openings 31 are located adjacent the air periphery ofthe compartments to provide initial discharge of the air and gaseousfluid from the compartments. Since the radial positioning of theopenings 31 in the plate 26' determines which of the fluids will bedischarged first, it will be seen that it is unnecessary to accuratelycontrol the radial positioning of the ports in the port plate 11, solong as these ports communicate with the openings 31 in the plate 26' atthe proper time.

Although the invention has been described in connection with certainspecific embodiments, the principles herein are susceptible to numerousother applications that will readily occur to persons skilled in theart. The invention is, therefore, to be limited only as indicated by thescope of the appended claims.

I claim:

1. A positive displacement pump and separating apparatus for separatingfluids of different densities comprising, a pump casing having spacedwalls defining a pump chamher, inner and outer eccentrically relatedrotors in said chamber having means extending therebetween defining aplurality of segregated pumping compartments having inner and outerwalls, plates attached to opposite sides of,

3 one of said rotors for rotation therewith and extending intooverlapping relation with the other of said rotors to enclose the sidesof the pumping compartments and reduce frictional drag between the fluidin the compartments and the walls of the chamber, one of said plateshaving a plurality of openings therein located closely adjacent one ofthe walls of the compartments and spaced radially from the other wallsof the compartments, means for rotating said rotors to centrifugallyseparate fluid in the compartments into inner and outer layers accordingto the relative densities of the fluids, said rotors being supported forrotation about relatively eccentric axes whereby the compartmentsprogressively expand during one portion of each revolution as they movepast an inlet zone and progressively contract during a different portionof each revolution as they move past a discharge zone, said casinghaving inlet port means communicating with said openings as they movepast said inlet zone whereby expansion of the compartments draws fluidin through the inlet port means, said casing having a first outlet portcommunicating with said openings as they move past a first sector ofsaid discharge zone and a second outlet port communicating with saidopenings as they move past a second sector of said discharge zone.

2. The combination of claim 1 wherein said openings are elongated in adirection circumferentially of the pumping compartments.

3. The combination of claim 1 wherein said openings are locatedrelatively closer to the lead side than to the trailing side of thecompartments.

4. A positive displacement pump and separating apparatus for separatingfluids of different densities comprising, a pump casing having spacedwalls defining a pump chamber, inner and outer eccentrically relatedrotors in said chamber having means extendingtherebetween defining aplurality of segregated pumping compartments having inner and outerwalls, said rotors being supported for rotation about relativelyeccentric axes whereby the compartments progressively expand during oneportion of each revolution as they move past an inlet compartment andprogressively contract during a different portion of each revolution asthey move past a discharge zone, plates attached to opposite sides ofone of said rotors for rotation therewith and extending into overlappingrelation with the other rotor to enclose the sides of the pumpingcompartments and reduce frictional drag between the fluid in thecompartments and the walls of the chamber, one of said plates having aplurality of openings therein located closely adjacent the inner wallsof the compartments and spaced inwardly from the outer walls of thecompartments, means for rotating said rotors to centrifugally separatefluid in the compartments into inner and outer layers according to therelative densities of the fluids, said casing having inlet port meanscommunicating with said openings as they move past said inlet zonewhereby expansion of the compartments draws fluid to be separated intothe compartments, said casing having a first outlet port communicatingwith said openings as they move past a first sector of said dischargezone whereby the initial contraction of the compartments forces fluidcontaining the lighter centrifugally separated components from thecompartments, and a second outlet port communicating with said openingsas they move past a second sector of said discharge zone wherebysubsequent contraction of the compartments forces fluid containing theheavier components from the compartments.

5. A positive displacement pump and separating apparatus for separatingfluids of different densities comprising, a pump casing having spacedwalls defining a pump chamber, inner and outer eccentrically relatedrotors in said chamber having means extending therebetween defining aplurality of segregated pumping comone portion of each revolution asthey move past an inlet compartment and progressively contract during adifferent portion of each revolution as they move past a discharge zone,plates attached to opposite sides of said inner rotor for rotationtherewith and extending into overlapping relation with said outer rotorto enclose the sides of the pumping compartments and reduce frictionaldrag be-! tween the fluid in the compartments and the walls of thechamber, one of said plates having a plurality of openings thereinlocated closely adjacent the inner walls of the compartments and spacedinwardly from the outer walls of the compartments, means for rotatingsaid rotors to centrifugally separate fluid in the compartments intoinner and outer layers according to the relative densities of thefluids, said casing having inlet port means communicating with saidopenings as they move past said inlet zone whereby expansion of thecompartments draws fluid to be separated into the compartments, saidcasing having a first outlet port communicting with said openings asthey move past a first sector of said discharge zone whereby the initialcontraction of the compartments forces fluid containing the lightercentrifugally separated components from the compartments, and a secondoutlet port communicating with said openings as they move past a secondsector of said discharge zone whereby subsequent contraction of thecompartments forces fluid containing the heavier components from thecompartments.

6. The combination of claim 5 wherein said ports in said casing areangularly spaced apart a distance approximately corresponding to theangular width of said openings in the plates.

7. A positive displacement type pump and separating apparatus forseparating fluids of different densities comprising, a pump casinghaving spaced walls defining a pump chamber, an internally toothed outerro'tor rotatably mounted in the chamber and a cooperating externallytoothed inner rotor having at least one less number of teeth than saidouter rotor, said rotors being supported for rotation about relativelyeccentric axes and the teeth on said rotors maintaining a close runningseal therebetween to define a plurality of segregated compartments thatprogressively expand during one portion of each revolution as they movepast an inlet zone and progressively contract during a different portionof each revolution as they move past a discharge zone, plates attachedto opposite sides of one of the rotors for rotation therewith andextending into overlapping relation with the other rotor to enclose thesides of the compartments and reduce frictional drag between the fluidin the compartments and the walls of the casing, one of said plateshaving a plurality of openings therein located closely adjacent theroots of the teeth on one of the rotors and spaced radially from theroots of the teeth on the other of the rotors, means for rotating saidrotors to centrifugally separate the fluid in the compartments intoinner and outer layers according to the relative densities of thefluids, said casing having inlet port means communicating with saidopenings as they move past said inlet zone whereby expansion of thecompartments draws fluid to be separated into the compartments, saidcasing having a first outlet port communicating with said openings asthey move past a first sector of said discharge zone whereby initialcontraction of the compartments forces a portion of the centrifugallyseparated fluid from the compartments through the first port, and asecond outlet port communicating with said openings as they move past asecond sector of said discharge zone whereby subsequent contraction ofthe compartments forces another of the centrifugally separated fluidsfrom the compartments.

8. A positive displacement type pump and separating apparatus forseparating fluids of different densities comprising, a pump casinghaving spaced wall defining a pump chamber, an internally toothed outerrotor rotatably mounted in the chamber and a cooperating externallytoothed inner rotor having at least one less number of teeth than saidouter rotor, said rotors being supported for rotation about relativelyeccentric axes and the teeth on said rotors maintaining a close runningseal therebetween to define a plurality of segregated compartments thatprogressively expand during one portion of each revolution as they movepast an inlet zone and progressively contract during a different portionof each revolution as they move past a discharge Zone, plates attachedto opposite sides of the inner rotor for rotation therewith andextending into overlapping relation with the outer rotor to enclose thesides of the compartments and reduce frictional drag between the fluidin the compartments and the walls of the casing, one of said plateshaving a plurality of openings therein located closely adjacent theroots of the teeth on the inner rotor and spaced radially from the rootsof the teeth on the outer rotor, means for rotating said rotors tocentrifugally separate the fluid in the compartments into inner andouter layers according to the relative densities of the fluids, saidcasing having inlet port means communicating with said openings as theymove past said inlet zone whereby expansion of the compartments drawsfluid to be separated into the compartments, said casing having a firstoutlet port communicating with said openings as they move past a firstsector of said discharge zone whereby the initial contraction of thecompartments forces fluid containing the lighter centrifugally separatedcomponents from the compartments, and a second outlet port communicatingwith said openings as they move past a second sector of said dischargezone whereby subsequent contraction of the compartments forces fluidcontaining the heavier components from the compartments.

9. The combination of claim 8 wherein said plates are thin as comparedto the axial width of the rotors.

10. The combination of claim 8 wherein said openings are elongated in adirection circumferentially of the inner rotor.

11. The combination of claim 8 wherein said openings are locatedrelatively closer to the lead side of the tooth spaces on the innerrotor than to the trailing side.

12. A- positive displacement rotary pump and separating apparatuscomprising, means including a casing having a chamber therein and arotor disposed in said chamher defining a plurality of expansible andcontractible pumping compartments arranged in an annular bank around therotor and having inner and outer walls, means for rotating said rotorabout an axis paralleling said annular bank to centrifugally separatethe fluids in the compartments, said rotor being located eccentricallyin said chamber whereby the inner and outer walls of the compartmentsmove away from each other during one portion of each revolution toprogressively expand the compartments as they move past an inlet zoneand the inner and outer walls move toward each other during a ditferentportion of each revolution to progressively contract the compartments asthey move past a discharge zone, inlet means including at least oneinlet passage com-i municating with said compartments as they move pastsaid inlet zone for supplying fluid thereto containing liquid andgaseous fluids of relatively different densities whereby expansion ofthe compartments draws the fluids to be separated into the compartments,plates attached to opposite sides of said rotor for rotation therewithand extending outwardly to enclose the sides of the pumping compartmentsand reduce frictional drag between the fluid in the compartments and thewalls of the chamber, one of said plates having a plurality of openingstherein located closely adjacent the inner walls of the compartments andspaced radially inwardly from the outer walls of the compartments, saidcasing having inlet port means communication with said openings as theymove past said inlet zone, said casing having a first outlet portcommunicating with said openings as they move past a first sector ofsaid discharge zone and a second outlet port communicating with saidcompartments as they move past a second sector of said discharge zone.

References Cited by the Examiner UNITED STATES PATENTS 2,053,919 9/1936Pigott 103-126 2,417,701 3/1947 Parsons 103-126 2,539,044 1/1951 Walsh103126 2,732,802 1/1956 Eames 103-426 2,871,831 2/1959 Patin 103-126SAMUEL LEVINE, Primary Examiner.

W. L. FREEH, Assistant Examiner.

1. A POSITIVE DISPLACEMENT PUMP AND SEPARATING APPARATUS FOR SEPARATING FLUIDS OF DIFFERENT DENSITIES COMPRISING, A PUMP CASING HAVING SPACED WALLS DEFINING A PUMP CHAMBER, INNER AND OUTER ECCENTRICALLY RELATED ROTORS IN SAID CHAMBER HAVING MEANS EXTENDING THEREBETWEEN DEFINING A PLURALITY OF SEGREGRATED PUMPING COMPARTMENTS HAVING INNER AND OUTER WALLS, PLATES ATTACHED TO OPPOSITE SIDES OF ONE OF SAID ROTORS FOR ROTATION THEREWITH AND EXTENDING INTO OVERLAPPING RELATION WITH THE OTHER OF SAID ROTORS TO ENCLOSE THE SIDES OF THE PUMPING COMPARTMENTS AND REDUCE FRICTIONAL DRAG BETWEEN THE FLUID IN THE COMPARTMENTS AND THE WALLS OF THE CHAMBER, ONE OF SAID PLATES HAVING A PLURALITY OF OPENINGS THEREIN LOCATED CLOSELY ADJACENT ONE OF THE WALLS OF THE COMPARTMENTS AND SPACED RADIALLY FROM THE OTHER WALLS OF THE COMPARTMENTS, MEANS FOR ROTATING SAID ROTORS TO CENTRIFUGALLY SEPARATE FLUID IN THE COMPARTMENTS INTO INNER AND OUTER LAYERS ACCORDING TO THE RELATIVE DENSITIES OF THE FLUIDS, SAID ROTORS BEING SUPPORTED FOR ROTATION ABOUT RELATIVELY ECCENTRIC AXES WHEREBY THE COMPARTMENTS PROGRESSIVELY EXPAND DURING ONE PORTION OF EACH REVOLUTION AS THEY MOVE PAST AN INLET ZONE AND PROGRESSIVELY CONTRACT DURING A DIFFERENT PORTOIN OF EACH REVOLUTION AS THEY MOVE PAST A DISCHARGE ZONE, SAID CASING HAVING INLET PORT MEANS COMMUNICATION WITH SAID OPENINGS AS THEY MOVE PAST SAID INLET ZONE WHEREBY EXPANSION OF THE COMPARTMENTS DRAWS FLUID IN THROUGH THE INLET PORT MEANS, SAID CASING HAVING A FIRST OUTLET PORT COMMUNICATING WITH SAID OPENINGS AS THEY MOVE PAST A FIRST SECTOR OF SAID DISCHARGE ZONE AND SECOND OUTLET PORT COMMUNICATING WITH SAID OPENINGS AS THEY MOVE PAST A SECOND SECTOR OF SAID DISCHARGE ZONE. 